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Product details
The EMPI 43-5307-0 is a 1.40 mm main jet for PMO carburetors and for the EMPI and Weber carbs EMPI lists for it (40/44 HPMX, 40/44/48 IDF, EPC 48/51, 48 IDA, and DCO/DCOE). PMO includes 43-5307-0 in its own main jet list and builds its carbs to accept standard IDF jets. In PMO's kit lineup, the 40mm kits step from 135 mains (2.4 to 2.7 liter) to 145 mains (2.8 to 3.0 liter), so the 1.40 is the half step between them.
That makes it a common move on a 911 that runs slightly lean on 135s or slightly rich on 145s. PMO notes its kit jetting assumes stock-port heads and factory-style cams, and that bigger ports, higher compression, or race cams need tuning beyond the kit. Keep every throat on the same size.
Technical Details
- Manufacturer: EMPI
- Manufacturer part number: 43-5307-0
- Jet type: main jet
- Size: 1.40 mm
- Carburetors: 40/44 HPMX, 40/44/48 IDF, EPC 48/51, 48 IDA, and DCO/DCOE
- Sold as: each
Fitment & Compatibility
Suits PMO carburetors and EMPI's applications above. Weber DGV and EMPI EPC 32/36 carburetors need a different jet.
Installation & Tuning Notes
Before changing jets, check for vacuum leaks, set valve lash and timing, fit fresh plugs, synchronize the carbs, and confirm float level (PMO carbs have a sight glass for this). Test at steady rpm in a higher gear rather than from a standing start. Change one part at a time and record each combination.
Common Questions
My PMO kit runs lean on 135s. Should I jump to 145?
Try the 1.40 first. It is the half step between the two sizes PMO uses in its 40mm kits.
Can I use this in a Weber IDA?
Yes. EMPI lists the 48 IDA along with the IDF, HPMX, EPC 48/51, and DCO/DCOE.
